Improvement in bit-clamps for boring-machines



F. DEZENDORF. Bit-Clamp for Boring-Machines.

Patented Dec. 18, 1877.

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ATTORNEYSZ N. PETERS. PHOTO-LITHOGRAPNEFI. WASHINGTON. D c

UNITED STATES PATENT OFFICE.

FREDERICK DEZENDORF, OF CORNWALL-ON-HUDSON, NEW YORK.

- IMPROVEMENT IN BIT-CLAMPS FOR BORING-MACHINES.

Specification forming part of Letters Patent No. 198,280, dated December 18, 1877; application filed November 3, 1877.

To all whom it may concern:

Be itknown that I FREDERICK DEZENDORF, of Oornwall-on-the-Eudson, in the county of Orange and State of New York, have invented a new and Improved Bit-Clamp, of which the following is a specification:

In the accompanying drawings, Figure 1 represents a side elevation of my improved bit-clamp, and Fig. 2 a vertical central section of the same.

Similar letters of reference indicate corresponding parts. A

This invention relates to an improved bitclamp for power-machines, which is quickly adjusted to ditterently-sized shanks of bits, so as to firmly hold and quickly release the same without working loose by the motion of the machine; and the invention consists of two bit-holding jaws, that are fulcrumed to the ends of a rigid T-piece of a threaded centerpiece, the jaws being adjusted by a conical nut turning on the threaded centerpiece, and acting on the upper concaved ends of the jaws.

Referring to the drawings, A represents the center-piece, that is screwed into the lower end of the stock of the power-machine, the lower part of the same being threaded in opposite direction to the thread on the upper part, and provided at the lower end with a fixed cross-head or T-piece, B, that is rigidly keyed thereto.

To the recessed ends of the T-piece B are fulcrumed the jaws G, which are provided in the customary manner, at the inside, with angular recesses or grooves a, for taking hold of the bit-shanks, in connection with a square socket-hole, b, of the center-piece.

A conical nut, D, works on the lower screw portion of the center-piece, and bears on the concaved upper ends of the jaws, so as to bring the lower ends closer together when the screwnut is turned, while admittingthe ready spreading or opening of the jaws or screwing the nut up. By turning the nut down, a bit-shank of any size may be firmly clamped for work, and

by turning the nut up the same may be quick 1y taken out. The screw-nut D is provided with holes for the insertion of an adjusting lever-pin, by which the required turns of the nut are readily given until the shank is firmly clamped or released.

In this manner a powerful and quickly-adj usted bit-clamp for bit-shanks of all sizes is furnished that is self-centering, and holds a bit so as not to work loose by the motion of the machine, griping all ordinary bit-shanks and auger-shanks equally well, and being readily attached to the stock of a power-machine by the threaded shaft.

Having thus described my invention, I claim as new and desire to secure by Letters Patent A bit-clamp for power-machines, consisting of athreaded center-piece,with bottom T-piece, fulcrum'ed jaws, and a verticallyadjustable conical screw-nut bearing on the upper ends of jaws, for setting them to the bit-shank, substantially in the manner set forth.

FREDERICK DEZENDORF.

Witnesses CHAS. E. CoLDwnLL, DANIEL DRIscoLL. 

